Field of the Invention
This application relates to quantification of space and volume of areas in a patient's anatomy. In some aspects, this application relates specifically to mitral valve quantification. Even more specifically, this application relates to a system and method for quantifying the mitral valve apparatus and its surroundings for use in selecting an appropriately sized valve in a catheter-based transcatheter mitral valve repair procedure.
Description of the Related Technology
The human heart is a complex organ having many working parts which are critical to the proper functioning of the heart and the blood circulation and provides throughout the human body. The human heart is generally made up of four hollow chambers, the right atrium, the right ventricle, the left atrium, and the left ventricle. One of the keys to a properly functioning heart is the regulation of blood flow through these chambers. Regulation of blood throw through and between these chambers is provided by valves. For example, between the right atrium and the right ventricle, there is an atrioventricular opening.
The tricuspid valve is situated at that opening, and permits blood to move from the right atrium into the right ventricle. The valve opens when the blood pressure on the atrium site is greater than that on the ventricular side. When the valve opens, blood is permitted to flow from the right atrium into the right ventricle. When blood pressure is greater on the ventricle side, the valve closes. When the valve closes, blood is prevented from moving back in the other direction.
In the healthy heart, blood flow is also regulated between the left atrium and left ventricle. Here, the mitral valve allows blood to enter the left ventricle from the left atrium when the left atrium fills with blood and the pressure within the left atrium increases to a level above that of the left ventricle. When open, blood flows in a downward direction from the left atrium into the left ventricle, where it is pushed out to the rest of the body as part of the greater circulatory process. When a healthy mitral valve closes, blood flow between the two chambers stopped, and this closing prevents a reversal of blood flow.
Unfortunately, mitral valves do not always function normally. An abnormally functioning mitral valve can lead to severe health problems. One abnormality associated with the mitral valve is mitral regurgitation (“MR”). Mitral regurgitation is a disorder in which the mitral valve does not close properly during contraction of the left ventricle. This causes blood that has passed from the left atrium into the left ventricle to reverse its flow back into the left atrium.
Mitral regurgitation may be treated surgically. One surgical option includes the replacement of the mitral valve where the mitral valve is replaced with either a bio prosthetic replacement or a synthetic replacement. Another surgical option includes repair of the mitral valve. Although mitral valve repair is generally seen as preferable to mitral valve replacement due to the less invasive nature of the procedure, at present, both options require open-heart surgery. Because many candidates for mitral valve replacement and repair are not good candidates for tolerating the stress of open-heart surgery, there has been ongoing research directed to developing transcatheter mitral valves. These transcatheter mitral valves can be introduced using a catheter-based system, obviating the need for a surgical procedure. Using noninvasive catheter-based implant techniques, the physical trauma associated with an open heart surgery may be minimized and more patients may be treated effectively for the mitral regurgitation disorder.
Although the use of transcatheter mitral valves shows great promise, there are significant challenges involved with effectively deploying these types of devices. In an open surgical procedure, the surgeon has complete access to the surgical site. Consequently, the surgeon is able to visually survey the site in order to perform the procedure effectively. When using the catheter-based system, however, the surgeon must rely and various imaging technologies to provide guidance to positioning and fit of a repair and/or replacement valve. Because transcatheter mitral valves are inserted using a delivery catheter, it is critical that the transcatheter mitral valve introduced into the patient have an appropriate size and shape to conform to the patient's anatomy. The need for appropriate sizing and shaping of implants extends well beyond mitral valve-related procedures, and may be useful in various different surgical contexts. At present, methodologies for quantifying the pertinent measurements of the mitral valve are inadequate. Accordingly, there is a need for a standardized measurement method which can be used for planning implantation of medical devices, including transcatheter mitral valve implantation.